As @d5000 mentioned above, Local Boards on aggregate constitute the most merited area, but we should consider that we’re aggregating 21 Local Boards here... That’s a large mass we’re aggregating (half of the subsections on all Bitcointalk). There are some local boards which from the overall perspective may seem really merited (Russian, Turkish and Indonesian are amongst the most), but this should be seen as relative to the number of posts on these boards, since the number of total merits on these boards does not reflect this and may be misleading.

Take a look at a post I created not too long ago: Bitcointalk – Posts per Day - evolution during past six months. Specifically checkout a section called "4. Merits per post Ratio". There you will see a column called "Merit/post" which tell us just that. The ratio of each individual local boards is not that great, and certainly does not standout.

I can speak for the Spanish Local board. I have not seen any merit exchange or abuse there. What there is there a smallish pool of good posters, way above the average in terms of quality. These standout of the crowd and substantially contribute to the local forum richness. They are therefore amongst the most merited there due to being good at posting, and nothing else that I’m aware of. Nevertheless, merit there is distributed at a very slow pace, being 79,89% of TXs of a single sMerit, and 88,28% of the posts merited by a single person.

In fact, I published yesterday a list of the members that have needed merit to rank-up there: Only 22 people have ranked-up so far needing merit in the process. Out of those, 5 people have received all their merit on the Spanish local board, whilst the remaining 17 have had to emigrate in a sense to get a large part of their merits on the regular English boards … not really that great.